Wireless communication systems have been widely deployed to provide various types of communication services such as voice or data services. In general, a wireless communication system is a multiple access system capable of supporting communication with multiple users by sharing available system resources (bandwidth, transmit power, etc.). Multiple access systems include, for example, a code division multiple access (CDMA) system, frequency division multiple access (FDMA) system, time division multiple access (TDMA) system, orthogonal frequency division multiple access (OFDMA) system, and single-carrier frequency division multiple access (SC-FDMA) system.